Study on cutting performance of diamond-coated rhombic milling cutter in machining carbon fiber composites

The anisotropy characteristic of carbon fiber reinforced plastic (CFRP) easily results in defects such as delamination, tear, and burr in the milling procedure, which seriously restrict its widespread application. Thus this work conducted an experimental research in the cutting performance of the diamond-coated rhombic milling cutter in machining carbon fiber composites. Tool wear procedure and wear mechanism were analyzed, and the variation of both surface quality and cutting force under different tool wear conditions were obtained. It was found that the tool wear process can be divided into two stages, that is, coating wear dominated by abrasive wear and coating shedding by fatigue wear mechanism. In the stage of coating wear, the machined surface of carbon fiber composites was flat and regular, and chips were mainly granular. Whereas in the stage of coating shedding, cutting forces increased substantially; some defects such as stratification, tearing, and fiber pull-out got to occur on the machined surface, and lots of burrs were produced at the edge of machined surface. And here chips were a blend of granular and long-strip ones. The analysis of tool wear mechanism and machined surface morphology in machining carbon fiber composites can provide a significant theoretical reference to improving the machining quality of carbon fiber composites.